An electronic apparatus, such as a mobile phone and a laptop personal computer (hereinafter, called laptop PC), employs a configuration in which a display chassis is rotatably connected to a main-body chassis by a hinge device.
For example, there has been known a laptop PC that includes hinge devices on a rear end of a main-body chassis to be able to rotate a display chassis from a 0-degree position to a 360-degree position (e.g., see Japanese Patent Application Laid-Open No. 2017-33116). Such a laptop PC improves convenience by employing different modes in accordance with open angles. For example, modes according to the open angles of a hinge include a closed mode of 0 degrees, a laptop mode of about 10 degrees to 190 degrees, a stand mod or a tent mode of about 190 degrees to 350 degrees, and a tablet mode of 360 degrees. Herein, the stand mod is a mode in which a keyboard side of the main-body chassis is made be in contact with a surface of a desk to make a display face a user. The tent mode is a mode in which the main-body chassis and the display chassis are placed on the surface of the desk in the shape of a tent. The tablet mode is a mode in which the display can be used in a state where it is held by a hand of the user while facing a face of the user. Such a laptop PC includes acceleration sensors respectively provided in the main-body chassis and the display chassis to obtain the open angle of the hinge by computation from accelerations detected by the acceleration sensors.
To ensure high operation in the keyboard of the laptop PC, it is necessary to ensure a certain level of keystroke. To avoid causing the display to interfere with the keyboard on the upper surface of the main-body chassis when closing the display chassis while realizing the thinness of the main-body chassis, it is preferable that the keys of the keyboard be automatically depressed when closing the display. Such a key depressing mechanism is disclosed in Japanese Patent No. 5980374.
In the laptop PC disclosed in Japanese Patent Application Laid-Open No. 2017-33116 and Japanese Patent No. 5980374, timings of the switching between modes and the depressing operation of keys are based on an open angle between the main-body chassis and the display chassis. When using acceleration sensors to detect the open angle of the hinge in the laptop PC, response delay occurs because stability and computation of signals require some time. Moreover, in the case of the use for a mobile, an acceleration may be further added as a disturbance in addition to the opening and closing of the hinge, and thus there is a concern to have an influence on detection accuracy. Furthermore, because acceleration sensors are respectively provided in the main-body chassis and the display chassis, a system is complicated.
If a hinge device and an electronic apparatus, which can detect the open angle and the opening/closing angular velocity of a hinge in real time, are realized, it is considered that new use applications are added to the distinction of operation modes as described above, but sensing has response delay under the present situation.
The present invention has been made in consideration of the above problem, and an object of the invention is to provide a hinge device that can detect at least one of an open angle and an opening/closing angular velocity with high responsiveness and simple configuration and an electronic apparatus that includes the hinge device.